Re: {Collins} KWM-1 Feed through Capacitor Mod Completed

I have a bunch of these feed through caps,new old stock.


Sent from my iPad

On Jul 4, 2013, at 7:25 PM, William Yates <veniceamplifier@xxxxxxx> wrote:

> Greetings and Happy 4th to the list
> I had my KWM-1 apart for some routine maintenance and figured I should go ahead and replace
> the "soon to die at any moment" feed through capacitor by using a simple modification that has
> been discussed here previously. I took the chance of using two 600 volt .02uf 715P series Sprague
> Orange Drops wired in series. The small ceramic stand off insulator worked perfectly because the
> hole in the sub chassis where the old cap was mounted gave sufficient room for the "male" portion
> of the insulator to mate through with the "female" portion. Soldered the caps from the anode to ground.
> So far, it works great. I noticed not a single problem after testing on air and leaving on for a considerable
> amount of time. With 1200 volts rating and .01 capacity measured with my trusty Sencore tester, it measured out
> to .012 which seems fine to me... the old cap also measured .012 which is also fine by me.
> I would have very much rather used a ceramic type but I could not source one in my stashes of caps,
> so I took a chance. I have 100's of the wrong values rated at 2KV but not .01uf.
> Bill Carns handed out some very good info regarding the choices and types that are favorable for this
> application. I took some Hi resolution photos of the installation to give readers an idea of how I managed
> to mount the components should anyone desire to see them.
> The beauty of this modification is that it can be done for less than 1 dollar, and about 1 hour of time...
> the KWM-1 has a boatload of chassis screws! After 54 years of service, I think Sprague did a remarkable
> job of designing and building the feed through capacitors. A real testament to American craftsmanship.
> Then again, it's not surprising that Collins Radio chose certain makes and types of materials in which to 
> construct these wonderful pieces of equipment.
> For future reference, I plan to write an article outlining some techniques for cleaning the tune and load
> inductors. This is a very tricky and concise procedure that must be adhered to! Cuz, They Ain't making this
> stuff No Mo! I look forward to Sunday's net where the KWM-1 will finally be back on the air.
> I simply could not find the guts to check in with non Collins gear., hence my absence.
> 73 and Happy 4th!
> Billy N6YW
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